Compile and run:

#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

#define DIRNAME "dcache-test-dir"

int main(void) {
        int i = 0;
        char dir[1024];
        
        getcwd(dir, sizeof(dir));
        
        while (1) {
                if (mkdir(DIRNAME, S_IRWXU) < 0) {
                        perror("Can't mkdir");
                        break;
                }
                if (chdir(DIRNAME) < 0) {
                        perror("Can't chdir");
                        break;
                }
                i++;
        }

        printf("Created/entered into %d directories!\n", i);
        /* Cleanup */
        chdir(dir);
        system("rm -rf " DIRNAME);
        return 1;
}

I've seen CPU soft lockup message first, and several minutes after that - OOM handler has started to kill random processes. Tested on kernels 2.6.9-78.0.17.el4 and 2.6.18-137.el5.